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Re: How to rise the secondary? (fwd)
---------- Forwarded message ----------
Date: Mon, 13 Jul 1998 00:22:50 -0400
From: Richard Hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: How to rise the secondary? (fwd)
Tesla List wrote:
> ---------- Forwarded message ----------
> Date: Fri, 10 Jul 1998 23:37:10 +0000
> From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: How to rise the secondary? (fwd)
>
> Richard, et al -
> Do you (or R. Hull) have any test data that would show how much the
> streamer loading, etc. capacitance is and how much it affects the operating
> frequency after the toroid mounting capacitance change is taken into
> consideration? As I indicate above the operating frequency change for only
> the streamer loading, etc. should be very small.
...........................Streamer loading on a real big system is extreme.
Nemesis' instrumented resonance with top load was 66khz. Running, for best
spark, another whole turn was required to go to 54khz. I learn quickly to drop
the calculations and expect at least a full extra turn on all primaries where a
toroid was used whose diameter was in excess of 100% the coil height. After
1992 all of my magnifiers used toroidal diameters which approach 200% of the
resonator coil height. Maggey 11-E uses a 46" diameter toroid on a 12" long
resonator. R. Hull
.............................
> I like to look at the longest sparks as the condition where the TC input
> energy equals the output energy plus the losses. When the losses are the
> lowest the maximum energy appears in the secondary circuit and the sparks
> are the longest. In other words the longest sparks happen when the maximun
> energy at the maximum potential occurs on the topload. The length of the
> first spark depends on the potential and additional sparks are then modified
> by the ionozation of the air. The energy and potential are related by
> Joules = 1/2 Cs Vs^2
> This should be multiplied by an efficiency if one can be determined.
> Note that a large amount of power can mean large currents and low potential
> producing short sparks.
>
> John Couture
>
> -----------------------------------------------------
>
> At 11:50 AM 7/9/98 -0600, you wrote:
> >
> >
> >---------- Forwarded message ----------
> >Date: Thu, 9 Jul 1998 18:02:13 +0100
> >From: R M Craven <craven-at-globalnet.co.uk>
> >To: Tesla List <tesla-at-pupman-dot-com>
> >Subject: Re: How to rise the secondary? (fwd)
> >
> >John Couture, in reply to Bill the arcstarter, wrote:
> >
> ><snip>
> >> You are correct in saying that "the really tricky one is Cs". The Cs
> >>includes the toroid cap which is changed to an unknown value when mounted
> >on
> >>the TC. However, the true Cs and toroid capacitances can be found after the
> >>TC is built and tested to find the true operating frequency. You then vary
> >>the toroid cap value in repeated manual calculations with the several
> >>parameters involved until the test frequency shows up in the output. The
> >new
> >>total secondary capacitance (Cs) will be the true total capacitance. The
> >new
> >>toroid capacitance being used will be the true capacitance of the toroid
> >>when mounted on the TC.
> >
> ><snip>
> >
> >Whilst this is all established, the fact is that the operating conditions
> >are different from instrumented conditions, and additionally operation at
> >full power is different from operation at lower powers.
> >
> >Richard Hull and many others, myself included, commented ages ago when we
> >were all discussing toroid sizes, optimums, expressions for calculating
> >toroid capacitance. The apparent increase in total secondary C due to
> >streamer loading, brush discharge and localised ionisation, mean that the
> >topload "looks" more capacitive than when output effects are not occurring
> > by which I mean St Elmo's fire through brush discharge through to arcs).
> >
> >That is why people recommend doing a static setup based on calcs, then
> >running at lower power, then empirically tuning the pri out a couple of
> >turns. Then, the loading effect that occurs as topload "activity" increases,
> >causes the self-res freq. of the sec to lower, and match the already
> >intentionally-lowered primary frequency.
> >
> >As for longer sparks, it's a question of minimising all of the spurious
> >"effects" and concentrating all of the available power into one channel,
> >keeping it alive, and promoting it before it can extinguish. That is why
> >there are differences between achieving a maximum potential difference on
> >the topload, and getting the longest sparks. They aren't the same thing! It
> >is through-power that is the goal.
> >
> >Richard Craven, Malvern, England
> >
> >